The present invention relates to magnetic bearing devices for rotating a rotary body as magnetically supported by magnetic bearings without contact.
Magnetic bearing devices, for example, for use in turbo molecular pumps of the magnetic bearing type comprise a machine main body having position sensors for detecting the position of a rotary body and magnetic bearings for magnetically contactlessly supporting the rotary body, and control means for controlling the magnetic bearings based on the signals from the position sensors. While many magnet bearing devices produced by a certain manufacturer are used by users at widely separated locations, the bearing devices are independent of one another and are conventionally controlled and maintained individually. Accordingly, the magnetic bearing device can not be checked for operating state or for the diagnosis of failure at a place other than the actual location of the device (the site of installation of the device for the user). Although the device as installed requires periodic maintenance, the manufacturer is unable to recognize or grasp the operating state of the device as stated above, so that every time need arises, the manufacturer must dispatch the technician to the site for him to grasp the operating state or to diagnose failure and to thereafter adjust the control means. Since such work at the installation site must be performed for each of the magnetic bearing devices of the users at various remote locations, there is the problem that the work requires much time and labor. Further the control circuits of the control means of magnetic bearing devices comprise an analog circuit and digital circuit. In the case of either circuit, a need is likely to arise to improve or alter the magnetic bearing control characteristics during use. In such an instance, the manufacturer must dispatch the technician to the site for the adjustment of the control circuit as in the above case.
An object of the present invention is to overcome the foregoing problems and to provide a magnetic bearing device which is accessible from a remote location for the recognition of the operating state thereof and for the adjustment of control means thereof.
The present invention provides a magnetic bearing device characterized in that the device comprises a machine main body having position sensors for detecting the position of a rotary body and magnetic bearings for magnetically contactlessly supporting the rotary body, control means for controlling the magnetic bearings based on signals from the position sensors, data processing means installed at a location away from the control means, and communication means for connecting the control means to the data processing means by communication lines.
The communication means connecting the control means to the data processing means allows data communication between the control means and the data processing means, making it possible to grasp the operating state of the machine main body or to adjust the control means using the data processing means as installed at a remote location.
The communication means, which is preferably one allowing interactive communication between the control means and the data processing means, is one at least enabling the control means to transmit communications to the data processing means.
In the case where communications are transmitted only from the control means to the data processing means, for example, data relating to the operating state of the machine main body (e.g., data as to the position of the rotary body or data as to control current values for the magnetic bearings) is sent to the data processing means via the communication means.
This enables the data processing means to recognize the operating state of the machine main body. When the data processing means is installed at the location of the manufacturer, therefore, the manufacturer can grasp the operating state of the machine main body without dispatching the technician to the installation site. It is also possible to diagnose failure from the data relating to the operating state, and even if the result of diagnosis indicates a need to adjust the control means at the site, it is only the adjustment of the control means that must be made at the site. The work time at the site can then be shortened. Further if only the adjustment of the control means is necessary, the user""s technician may be able to meet the need.
In the case where the control means and the data processing means are adapted for interactive communication therebetween, the control means, for example, transmits data relating to the operating state of the machine main body to the data processing means through the communication means, and the processing means transmits control parameters for the magnetic bearings to the control means through the communication means.
As in the foregoing case, the data relating to the operating state of the machine main body and transmitted from the control means to the data processing means enables the processing means to grasp the operating state of the machine main body, while the control means can be adjusted by transmitting the magnetic bearing control parameters from the processing means to the control means. When the data processing means is installed at the location of the manufacturer, therefore, the manufacturer is able to recognize the operating state of the machine main body, diagnose failure and adjust the control means without dispatching the technician to the site of installation. In this case, the data processing means may be adapted to automatically determine the data as to the control of the magnetic bearings, such as magnetic bearing control parameters, based on the machine main body operating state or the result of diagnosis of failure, or the technician may determine the data and input the data to the data processing means.
For example, the machine main body and the control means are provided in more than one set.
The sets of machine main body and control means may be installed at one location or at a plurality of separated locations.
It is then possible to grasp the operating state of machine main bodies at a remote location or remote locations or to grasp the operating state thereof and to adjust the control means by (one or a plurality of) common data processing means. Accordingly, the data processing means, when installed at the location of the manufacturer, enables the manufacturer to provide centralized supervision over the machine main bodies and control means which are installed at various locations for different users.
For example, the control means comprises an A/D converter for converting analog signals from the position sensors into digital position signals and outputting the digital position signals, a digital signal processor for determining control current values to be given to the magnetic bearings based on the digital position signals and outputting the values as digital control signals, and a D/A converter for converting the digital control signals into analog signals and feeding the resulting analog signals to the magnetic bearings.
The term the xe2x80x9cdigital signal processorxe2x80x9d as used herein refers to specific hardware adapted to receive digital signals and to deliver digital signals, programmable by software and operable for high-speed real-time processing. The processor will hereinafter be referred to as xe2x80x9cDSP.xe2x80x9d
When provided with the DSP, the control means is capable of processing signals at a high speed in real time.
For example, the control means comprises first memory means for storing data relating to the position of the rotary body and obtained from the position sensors and data as to the control current values determined by the digital signal processor for the magnetic bearings, and second memory means for storing magnetic bearing control parameters transmitted from the data processing means through the communication means. The digital signal processor feeds the data relating to the position of the rotary body and the data as to the control current values for the magnetic bearings to the first memory means, causes the first memory means to store the data and reads the magnetic bearing control parameters from the second memory means for use as new control parameters. The data processing means reads the data relating to the position of the rotary body and the data as to the control current values for the magnetic bearings from the first memory means through the communication means, transmits the magnetic bearing control parameters to the second memory means through the communication means and causes the second memory means to store the parameters.
The data processing means is then able to grasp the operating state of the machine main body and to adjust the control means.